Effect of different gasifying agents (steam,H2O2, oxygen,CO2, and air) on gasification parameters

Two sensitivity analyses were performed in an Aspen simulation of fluidized bed gasification for five different gasifying agents such as steam, hydrogen peroxide (H₂O₂), pure oxygen (O₂), carbon dioxide (CO₂), and air. In the first sensitivity analysis, the modified equivalence ratio (MER) was varied (0.22-0.36). For the varied modified equivalence ratio (MER), %hydrogen, H₂/CO molar ratio, and hydrogen yield were the highest in steam-gasification, but %carbon monoxide, %methane, CO yield, and the lower heating values (LHV) were the highest in CO₂-gasification. In the second sensitivity analysis, the freeboard temperature was varied (500-900 °C). With increasing freeboard temperature, %hydrogen and %carbon monoxide increased while %carbon dioxide and %methane decreased for all the gasifying agents. Also, with increasing freeboard temperature, the LHV decreased and the hydrogen yield, CO yield, and the gas production rate increased for all the gasifying agents, but the H₂/CO molar ratio increased only in oxygen, air, and CO₂-gasification.     

Applied whispering gallery modes on ZnO nanorods coated glass for humidity sensing application

In this letter, a humidity sensor is demonstrated by applying a whispering gallery mode (WGM) from a microsphere resonator onto the ZnO nanorods coated glass surface. The diameter of the microsphere was 234 µm and the glass surface was coated with ZnO nanorods using the hydrothermal method at growth duration of 12 h. A significant response to humidity level ranging from 35%RH to 85%RH has been observed with the sensitivity of 0.014 2 nm/%RH. The proposed humidity sensor has successfully employed to enhance interaction between the whispering gallery mode evanescent and surrounds analyte with the assistance of ZnO nanorods coated glass.     

Determination of heat transfer coefficients for hydrogen condensation in condensers of various geometries

An important task for the hydrogen isotopes separation by cryogenic distillation is to establish the shape and dimension of the column condenser and boiler in order to obtain the desired load and separation for the distillation column. In the paper we present the set-up and experimental values for the heat transfer coefficient on various types of condensers. The heat transfer coefficients were determined by measurements on liquid hydrogen flow-rate condensed on the cold surface and temperature drop between the cooling liquid and the condensate. The experiments were made for different vapor pressures and certain temperatures of the cooling liquid from the condenser. As results we determined the condensation heat transfer coefficients for different shapes and geometries of the condensers as a function of the condensate film temperature drop.     

Free convective visco-elastic flow with heat and mass transfer through a porous medium with periodic permeability

The problem of three dimensional free convective flow with heat and mass transfer of a visco-elastic fluid through a highly porous medium with periodic permeability has been investigated. The porous medium is bounded by an infinite vertical porous plate with constant suction. The free stream velocity is supposed to be uniform. The analytical expressions for dimensionless skin-friction, the rate of heat transfer, the rate of mass transfer have been obtained and these results have been presented graphically for different values of the flow parameters involved in the solution.     

Effect of fuel blend composition on hydrogen yield in co-gasification of coal and non-woody biomass

In this study, torrefaction of sunflower seed cake and hydrogen production from torrefied sunflower seed cake via steam gasification were investigated. Torrefaction experiments were performed at 250, 300 and 350 °C for different times (10–30 min). Torrefaction at 300 °C for 30 min was selected to be optimum condition, considering the mass yield and energy densification ratio. Steam gasification of lignite, raw- and torrefied biomass, and their blends at different ratios were conducted at downdraft fixed bed reactor. For comparison, gasification experiments with pyrochar obtained at 500 °C were also performed. The maximum hydrogen yield of 100 mol/kg fuel was obtained steam gasification of pyrochar. The hydrogen yields of 84 and 75 mol/kg fuel were obtained from lignite and torrefied biomass, respectively. Remarkable synergic effect exhibited in co-gasification of lignite with raw biomass or torrefied biomass at a blending ratio of 1:1. In co-gasification, the highest hydrogen yield of 110 mol/kg fuel was obtained from torrefied biomass-lignite (1:1) blend, while a hydrogen yield from pyrochar-lignite (1:1) blend was 98 mol/kg. The overall results showed that in co-gasification of lignite with biomass, the yields of hydrogen depend on the volatiles content of raw biomass/torrefied biomass, besides alkaline earth metals (AAEMs) content.     

Impact of traps on DC,analog/RF,and linearity performance of Ferro-TFET

Silicon - In this article, we investigated the influence of non-identical interface trap charges (ITCs) (positive or donor and negative or acceptor) on the behavior of ferroelectric gate oxide...